The present invention relates to instruments for carrying out dental procedures, and more specifically to carrying out such procedures using a high pressure liquid jet.
It is known in the prior art and in common dental practice to carry out most treatments using mechanical techniques. For example, in endodontics, which often involves many root canal procedures, a diseased tooth is first diagnosed, and then an opening is drilled through the crown of the tooth into the pulp chamber thereof. After the tooth is isolated and the field sterilized, the pulp, consisting primarily of blood-rich tissue and nerve fiber and necrotic components, is then aspirated. There remains within the pulp chamber the primary nerve fibers and blood vessels that sustain the tooth. These tissues extend from extremely fine openings in the apex of the root(s) of the tooth through a narrow channel(s), and cannot be removed solely by aspiration.
Typically, a file is then inserted into the narrow channel(s) to displace and abrade the nerve and blood vessel tissue. Increasingly larger files are inserted, whereby the narrow channel(s) is cleared of all soft tissue. After cleaning and preparation, the pulp chamber and root channel(s) are filled with a sterile solid material, and the drilled opening is filled with standard gold, silver, or other dental filling preparations.
This typical procedure is labor-intensive, resulting in a high cost factor for the dentist's time as well as skill and experience. Moreover, the procedure may be painful, and sufficient local anesthetic must be injected to completely numb the area of the tooth for the relatively long time that the procedure requires.
Complications known to result from a root canal procedure may include infection arising from incomplete removal of the diseased tissue within the canal and pulp chamber, or the introduction of other infectious bacteria into those spaces during the procedure. In addition, the dentist may inadvertently perforate the tooth; e.g., by driving a file instrument through the apical opening at the base of the root, and the opening thus formed may provide a vector for renewed infection and inflammation. Not infrequently, drug therapy including a strong antibiotic is prescribed after the procedure to forestall these complications. Other complications include broken instruments lodged in the tooth, or fracture of the root or body of the tooth.
Recent innovations in this dental procedure include the use of laser light delivered into the pulp chamber and root channel by an optical fiber. The high power optical energy vaporizes the pulp and nerve tissue, and is inherently sterilizing. However, the products of tissue combustion may contaminate the interior of the chamber and root channel, and the laser pulses may not contact all of the tissue in the narrow root channel, causing very unsatisfactory results. To avoid these results, there is a tendency to apply an excess of laser energy, which may overheat the tooth and surrounding tissue and cause necrosis. In addition, laser energy impacting on pre-existing metallic fillings may cause dangerous reflected beams and unforeseen damage.
As another example, in periodontal practice, which typically includes gingivectomy procedures, the gingiva are usually resected using a scalpel, and scaling and root planing are accomplished with specialized steel tools. These procedures and most other dental procedures are executed with mechanical drills, burrs, and cutting wheels.
Innovations such as ultrasound-driven scaling instruments, high power lasers for caries removal, and the like have not substantially altered the reliance of the dental profession on the same mechanical tools that have been in use for almost a century. All such mechanical tools generate high levels of vibration and sound that are directly conducted through bone to the ears of the patient, resulting in patient comfort problems. Also, the mechanical tools, as well as ultrasound tools, generate substantial amounts of heat in very localized areas, causing direct pain stimulation. Water spray devices are provided to remove this heat, but may not be effective at the point source of the heat. In this regard, the heat generated by dental lasers may pose the greatest problem.
Clearly the prior art shows an unmet need for improved dental instruments that can carry out a wide range of dental treatment procedures without generating heat, noise, and vibration as they operate on the patient's teeth.